Method and apparatus for metal removal ion exchange

ABSTRACT

The present invention provides a method for selectively removing metal ions of interest from a solution ( 12 ), such as the wastewater from a chemical mechanical polishing process. The method comprises contacting a solution ( 12 ) containing solid particles, an oxidizing agent and a first concentration of the metal ions with an ion-exchange resin ( 20 ), such as a crosslinked poly-4-v resin, that is resistant to damage by the oxidizing agent and that is operative when in contact with the solution ( 12 ) to exchange selected ones of the metal ions in the solution for selected preferred ions in the ion-exchange resin thereby to produce a treated solution ( 22 ) having a second concentration of the metal ions that is lower than the first concentration. The present invention also relates to an apparatus ( 100 ) and system ( 500 ) for use with the method of the present invention.

The present application is a 35 U.S.C. 371 national stage application ofinternational application PCT/US01/00174, filed Jan. 3, 2001, and claimsthe benefit of U.S. Provisional Application No. 60/174,469, filed Jan.3, 2000.

FIELD OF THE INVENTION

The present invention generally relates to the removal of transition andheavy metal ions from an industrial waste stream. More particularly, thepresent invention is directed to the removal of copper ions from a wastestream generated during semiconductor manufacture. Specifically, thepresent invention relates to a novel method for removing copper fromsolution, and an apparatus for use therewith. Additionally, the presentinvention includes methods and apparatus for treating and processingindustrial waste streams from which copper has been removed according tothe method of the present invention.

BACKGROUND OF THE INVENTION

The semiconductor industry is continually seeking new ways for improvingand increasing the speed of integrated circuits. One method currentlyemployed by the semiconductor industry is the process of making copperinterconnects on integrated circuits, rather than the former method ofusing aluminum interconnects. Copper interconnects provide theadvantages of faster speed and better heat dissipation in integratedcircuits. The use of copper, however, presents certain problems in thefabrication process. In particular, the wastewater generated from thefabrication process contains copper instead of aluminum, making thewastewater toxic.

The process to create copper interconnects has the following basicoverall steps. First, copper is electroplated in and over the trenchesof the integrated circuit. The excess copper (outside of the trenches)is removed with a process termed Chemical Mechanical Polishing (CMP).CMP is a hybrid process where copper is polished off the wafer by acombination of chemical etching and physical polishing by fine aluminumoxide slurry. The particle size distribution of the slurry rangesgenerally from 0.02 micron (200 Angstroms) to 0.10 micron (1000Angstroms). The rinsing wastes from both of these processes containvariable amounts of dissolved copper.

The rinsewater from the electroplating process is very similar torinsewater found in plating and circuit shops where copper is plated onmetals and circuit boards. In particular, the rinsewater containsdissolved copper salts such as CuSO₄, dilute acid, surfactants anddilute levels of other organic and inorganic enhancing agents. Therinsewater from the CMP process contains solids, chelating agents andoxidizers, and presents a significant challenge for waste disposalefforts.

The primary goal for waste disposal of the rinsewater from the CMPprocess is the removal of copper from the waste stream, withoutrequiring the removal of the solids or oxidizing agents. Whileion-exchange is an efficient technology to achieve copper removal,conventional ion-exchange resins would be damaged irreversibly whenoxidizers are present. Further, flow patterns of conventional resincolumns would cause the solids present in the rinsewater to plug thecolumns. Additionally, while activated carbon is often used to eliminateoxidizers because it acts as a good reducing agent, the pores ofactivated carbon particles are susceptible to plugging due to theparticle size distribution of the CMP slurry waste.

Accordingly, there remains a need to provide a new and improved methodfor removing copper present in industrial wastewater streams, and in CMPslurry in particular. There is a further need for unique materials andmethodologies for abatement of copper and/or recycling of the wastewaterfrom industrial chemical processes. Additionally, there is a need for anapparatus for use with the methods of the present invention for theremoval of copper and the treatment and processing of wastewater fromcopper CMP manufacturing processes. The present invention is directed tomeeting these needs.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a new and usefulmethod for removing transition and heavy metals from waste generated byindustrial processes.

It is another object of the present invention to provide an efficientmethod for selectively removing copper from a wastewater stream.

It is yet another object of the present invention to provide methodsusing new materials useful in removing copper from a wastewater streamcontaining solids and oxidizing agents.

A still further object of the present invention is to provide anapparatus operative to efficiently remove copper from a CMP wastewaterstream.

Yet another object of the present invention is to provide methods andapparatus for treating and processing a wastewater stream from whichcopper has been removed.

A further object of the present invention is to provide methods andapparatus for purifying and recycling water in the wastewater stream forreuse at a CMP tool.

According to the present invention, then, a method is provided forselectively removing metal ions of interest, such as copper ions, from asolution. The method comprises contacting a solution containing solidparticles, an oxidizing agent and a first concentration of the metalions with an ion-exchange resin that is resistant to damage by theoxidizing agent; such as a crosslinked poly-4-vinylpyridine resin, andReillex 402 and Reillex 425 resins in particular. The resin is operativewhen in contact with the solution to exchange selected ones of the metalions in the solution for selected preferred ions thereby to produce atreated solution having a second concentration of the metal ions that islower than the first concentration. It is contemplated that the solutioncontains solid particles having a size distribution of from 0.02 micronto 0.10 micron, such as a solution that is the wastewater from achemical mechanical polishing process. The ion-exchange resin maycomprise a plurality of ion-exchange resin beads contained in a resinvessel thereby to define a resin bed, and the step of contacting may beaccomplished by passing the solution in an up-flow direction through theresin vessel thereby to expand the resin bed. Such expansion may be from10% to 60%.

The ion-exchange resin may be contacted with a regenerant solution, suchas an acid or base solution, operative to exchange ions therein for themetal ions of interest contained in the ion-exchange resin, thereby toform a regenerant waste solution containing a salt of the metal ions ofinterest. The regenerant waste solution may be passed to anelectrowinning cell that is operative to reduce the metal ions to theircorresponding elementary metal. The ion-exchange resin may also becontacted with a first rinse solution, such as de-ionized water, therebyto form a second rinse solution, which may be passed to a regenerantsource vessel to which a regenerant concentrate may be added thereby toform the regenerant solution in the regenerant source vessel.

The treated solution may be further processed, such as by adjusting thepH and oxidation-reduction potential of the treated solution, filteringby reverse osmosis, passing the solution through an electro-deionizationsystem, and/or passing the solution through a UV/vacuum degasificationsystem.

The present invention also relates to an apparatus for selectivelyremoving metal ions of interest from a solution containing an oxidizingagent and a first concentration of the metal ions. The apparatuscomprises an inlet adapted to receive the solution from a solutionsource, a resin vessel in fluid communication with the inlet and adaptedto receive the solution therefrom, an ion-exchange resin disposed in theresin vessel, a first outlet in fluid communication with the resinvessel and adapted to receive a treated solution therefrom, a regenerantsource in fluid communication with the resin vessel and operative toselectively provide thereto a regenerant solution, a second outlet influid communication with the resin vessel and adapted to receive aregenerant waste solution therefrom, and a valve system comprising aplurality of valves associated with a plurality of fluid pathwaysinterconnecting selected ones of the inlet, the resin vessel, theregenerant source and the first and second outlets. The second outletmay be adapted to be placed in fluid communication with anelectrowinning cell and to provide the regenerant waste solutionthereto. The apparatus may include a rinse source in fluid communicationwith the resin vessel and operative to provide a rinse solution thereto.The apparatus may further include various processing devices, includinga pH monitor, an oxidation-reduction potential monitor, areverse-osmosis device, a UV/vacuum degasification unit, and anelectro-deionization unit. The present invention contemplates apparatuscomprising a plurality of resin vessels and ion-exchange resinsrespectively disposed therein, wherein various valve states permit fluidflow along selected fluid pathways.

The present invention further contemplates a system for removing metalions of interest from a solution containing solid particles, anoxidizing agent and a first concentration of the metal ions. The systemcomprises a solution source, such as a CMP tool, operative to providethe solution containing the solid particles, the oxidizing agent and thefirst concentration of the metal ions, an ion-exchange apparatus, and ametal recovery apparatus, such as an electrowinning cell. The system mayfurther include a waste processing apparatus that includes at least onedevice selected from the group consisting of a reverse-osmosis device, aUV/vacuum degasification device and an electro-deionization device,and/or which is operative to adjust a pH and oxidation-reductionpotential of the treated solution to target values.

These and other objects of the present invention will become morereadily appreciated and understood from a consideration of the followingdetailed description of the exemplary embodiment of the presentinvention when taken together with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a diagrammatic view of the method according to the presentinvention;

FIG. 1 b is a diagrammatic view of optional regeneration andrinse/refill steps of the method of FIG. 1 a;

FIG. 1 c is a diagrammatic view of optional waste and regeneranttreatment steps of the method according to the present invention;

FIG. 1 d is a diagrammatic view of optional alternative waste processingsteps of the method according to the present invention;

FIG. 2 a is a diagrammatic view of a basic embodiment of an apparatusaccording to the present invention, showing a service cycle thereof;

FIG. 2 b is a diagrammatic view of the apparatus according to FIG. 2 a,showing a regeneration cycle thereof;

FIG. 2 c is a diagrammatic view of the apparatus according to FIGS. 2 aand 2 b, showing a rinse/refill cycle thereof;

FIG. 3 a is a diagrammatic view of a more preferred embodiment of thepresent invention, showing a service cycle of a first resin and aregeneration cycle of a second resin;

FIG. 3 b is a diagrammatic view of the apparatus according to FIG. 3 a,showing a service cycle of the first resin and a rinse/refill cycle ofthe second resin;

FIG. 3 c is a diagrammatic view of the apparatus according to FIGS. 3 aand 3 b, showing a service cycle of the second resin and a regenerationcycle of the first resin;

FIG. 3 d is a diagrammatic view of the apparatus according to FIGS. 3a–3 c, showing a service cycle of the second resin and a rinse/refillcycle of the first resin;

FIG. 4 is a diagrammatic view of a waste treatment or processingapparatus for use in treating the copper free waste produced by theion-exchange apparatus of the present invention;

FIG. 5 is a diagrammatic view of an alternative embodiment of a wastetreatment or processing apparatus for use in treating the copper freewaste produced by the ion-exchange apparatus of the present invention;and

FIG. 6 is a diagrammatic view of a copper bearing waste treatment systemaccording to the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

The present invention is directed to a method and apparatusincorporating a specialty ion-exchange resin for removal of metals froma stream of rinsewater generated by industrial manufacturing processes,such as copper CMP processes used in semiconductor manufacturing. Thepresent invention is especially advantageous in the ability toselectively remove copper without removing oxidizers or solids presentin the rinsewater stream. Additionally, the high degree of selectivityto transition and heavy metals allows the removal of copper withoutremoving aluminum or other components of the solution, which wouldotherwise result in a decrease in capacity of the resin. It should beunderstood that, while the present invention is particularly discussedwith respect to the removal of copper ions from a solution, the presentapplication contemplates applications involving the removal fromsolution of various transition or heavy metals.

As shown in FIG. 1 a, then, the present invention is directed to amethod 10 for removing metal such as copper from a selected environment,such as a copper bearing rinsewater stream 12. The method includes aservice cycle 16, which includes providing a copper bearing rinsewaterstream 12 from a source such as a feed tank 14 or other source operativeto provide copper bearing rinsewater stream 12. The copper bearingrinsewater stream 12 is then contacted with an ion-exchange resin 20which may be disposed in a resin vessel 18. The copper bearingrinsewater stream 12 that contacts the ion-exchange resin 20 undergoesion-exchange such that copper ions are captured by ion-exchange resin20. A treated solution, or copper free waste, 22 resulting from theion-exchange of copper bearing rinsewater stream 12 with ion-exchangeresin 20 may then be sent to a waste outlet 24 for disposal or furtherprocessing. It should be appreciated that while treated solution 22 isgenerally discussed herein as a “copper free waste”, treated solution 22generally includes any solution having a lower concentration of therespective metal ions of interest, such as copper ions, than theconcentration thereof in the original metal bearing rinsewater streamsolution 12 as a result of the ion-exchange of the present invention.

The preferred ion-exchange resin of the present invention is selectedfrom a family of crosslinked poly-4-vinylpyridine resins and derivativesthereof, such as those manufactured by Reilly Industries, Inc., 1500South Tibbs Avenue, Indianapolis, Ind. Exemplary ion-exchange resins aremanufactured under the tradenames Reillex™402 and 425. The vinylpyridinestructure of these resins makes them extremely resistant to attack byoxidizing agents, as compared for example to conventional resins thatare crosslinked by divinylbenzene. Additionally, the crosslinkedpoly-4-vinylpyridine resins and derivatives thereof are very selectiveto transition and heavy metals. This provides an added advantage whenaluminum or oxides of aluminum are present in the rinsewater steam,given that it becomes possible to remove copper as desired withoutunnecessarily removing aluminum. Conventional resins would remove bothcopper and aluminum, resulting in loss of capacity of the resin forcopper removal. Other ion-exchange resins contemplated for use with thepresent invention are discussed, for example, in U.S. Pat. Nos.5,281,631, 5,449,462, and 5,539,003 to Horwitz et al., which relate tophosphonic acid based ion exchange resins.

As shown in FIG. 1 b, the method according to the present inventionoptionally includes a regeneration cycle 26 and a rinse cycle 28. Thestep of regenerating includes contacting a regenerant solution 30, suchas an acid solution, provided by regenerant source 32 with theion-exchange resin 20. Regenerant solution 30 is selected according tothe requirements of ion-exchange resin 20, to the extent understood bythe ordinarily skilled artisan. Ion-exchange resin 20 is regenerated bycontact with regenerant solution 30, and regenerant waste solution 34containing copper ions is produced thereby. The copper bearingregenerant waste solution 34 is sent to regenerant waste collection 36for disposal or further processing, such as by an electrowinning cell.An exemplary electrowinning cell apparatus for use with the presentinvention is disclosed in application Ser. No. 09/322,745, filed May 28,1999, entitled Electrowinning Cell Incorporating Metal Ion FiltrationApparatus.

The rinse cycle 28 includes contacting ion-exchange resin 20 with arinse solution 38, such as de-ionized water, provided by rinse source40. Any regenerant solution 30 remaining in resin vessel 18 is rinsedtherefrom by rinse solution 38 to form regenerant rinse solution 42.Regenerant rinse solution 42 may then be sent to regenerant source 32where it may be recycled for use in forming regenerant solution 30, suchas by adding concentrated acid thereto.

As shown in FIGS. 1 c and 1 d, the method of the present invention mayoptionally include a waste and regenerant treatment step 46 oralternatively a waste processing step 48. With reference to FIG. 1 c,copper free waste 22 produced by the method of the present invention,and/or non copper CMP waste such as from other industrial processes 44,is sent to a waste tank 50. There it undergoes pH adjust and/oroxidation-reduction potential (ORP) adjust 52. The step of adjusting pHmay occur by monitoring pH such as with a pH monitor, and adding acid orbase as desired to reach a target pH. The step of adjusting ORP mayoccur by monitoring ORP such as with an ORP monitor to detect anoxidation-reduction potential, and adding for example NaHSO₃ to adjustORP as desired. The resulting solution may then be disposed of, such asby sending to sewer 54. Additionally, regenerant waste solution 34 fromregenerant waste collection point 36 may be further processed such as byelectrowinning cell 56.

With reference to FIG. 1 d, an alternative waste processing step 48includes sending copper free waste 22 from an ion-exchange apparatus 58,such as provided in the present invention, to a waste tank 50. Areducing agent may be added to waste tank 50, such as by monitoring ORPwith an ORP monitor and signaling a pump to pump a reducing agent intowaste tank 50 when an oxidation-reduction potential is detected. Reducedwaste 60 may then undergo reverse osmosis 62, which is preferably adouble pass R/O system especially configured to be suitable for highsolids in the feed stream, such as by utilizing polymeric spiral woundmembranes with wide spacers, or ceramic membranes. The R/O permeate 64may then be sent through a UV/vacuum degasification process 70 for traceorganics removal, which may comprise passing R/O permeate 64 through anorganic destruct UV lamp and then a vacuum degasser. The resultingpurified water 68 preferably further undergoes electro-deionization(EDI) 66.

A general embodiment of the apparatus 100 according to the presentinvention is shown in FIGS. 2 a–2 c. Here, apparatus 100 includes feedtank 114 operative to provide a Cu bearing rinsewater stream 112, resinvessel 118 having ion-exchange resin 120 disposed therein, regenerantsource vessel 132 having regenerant solution 130 disposed therein, rinsesource 140 operative to provide a rinse solution, waste outlet 124, hereshown as a container adapted to receive Cu free waste 122, andregenerant waste collection 136 operative to receive regenerant waste134. Feed tank 114, resin vessel 118, regenerant source vessel 132,rinse source 140, waste outlet 124 and regenerant waste collection 136are fluidly connected by conduit 172, which is adapted to receive afluid stream. Pumps 174 and 176 are disposed in conduit 172, and eachhave an on state wherein they are operative to pump fluid throughconduit 172 and an off state wherein they do not pump fluid. Valves 178,180, 182, 184, 186, 188, 189 and 190 are disposed in conduit 172 and areoperative to move between a closed state preventing fluid flowtherethrough and an open state allowing fluid flow therethrough.

FIG. 2 a shows the service cycle for apparatus 100. Here, Cu bearingrinsewater stream 112 is pumped from feed tank 114 by pump 174 inpreferably an upflow direction through resin vessel 118. Ion exchangeresin 120 accordingly expands, or fluidizes, as a result of the upflowdirection of travel of stream 112. Preferably, the bed of ion exchangeresin 120 expands approximately 25%, although a range of expansion of10%–60% is contemplated. Valves 178 and 180 are open, while theremaining valves are closed. Cu bearing rinsewater stream 112 flowsthrough resin vessel 118 where it undergoes ion-exchange with ionexchange resin 120, such that copper ions are captured by ion exchangeresin 120. Copper free waste 122, which may contain little or no copperions, is then passed from resin vessel 118 to waste outlet 124 where itmay be treated or processed, if desired, and either disposed of orrecycled in the manufacturing process.

When ion-exchange resin 120 is at full capacity of copper ions, aregeneration cycle begins as shown in FIG. 2 b. Here, valves 178 and 180are closed and pump 174 is turned off. Valves 182, 184, 186 and 189 areopened and pump 176 is turned on. Regenerant solution 130, preferably anacid solution such as sulfuric acid or alternatively a base solutionsuch as ammonium hydroxide, is pumped from regenerant source vessel 132and through resin vessel 118, where it undergoes ion-exchange withion-exchange resin 120, thereby to produce regenerant waste 134containing copper salt. The concentration, as well as rate of flowthrough resin vessel 118, of regenerant solution 130 is preferablyadjusted according to the concentration of regenerant waste 134 that isdesired.

Once ion-exchange resin 120 has been regenerated, a rinse cycle begins,as shown in FIG. 2 c. Here, valves 186 and 189 are closed and valves 188and 190 are opened, while pump 176 is turned off. Rinse solution 138,provided by rinse source 140, passes through resin vessel 118 to rinseany remaining regenerant solution 130 therefrom. Regenerant rinsesolution 142 then flows to regenerant source vessel 132, whereregenerant rinse solution 142 may be recycled to form a new regenerantsolution 130, such as by adding concentrated regenerant 192, preferablyconcentrated acid, to regenerant source vessel 132 until a desiredregeneration concentration of regenerant solution 130 is achieved. Tothe extent understood by the ordinarily skilled artisan, a concentrationmonitor/control or pH monitor/control may be used to automaticallyadjust the concentration of regenerant to regeneration levels by pumpingconcentrated solution to regenerant source vessel 132 as desired.

Once the rinse/refill cycle has completed, valves 182, 184, 188 and 190are closed and valves 178 and 180 are opened, and pump 174 is turned on,thereby to begin the service cycle again.

The various on/off and open/closed states of valves and pumps during theoperation cycles for apparatus 100 is summarized in Table 1 below:

TABLE 1 Service Regeneration Rinse/Refill Cycle Cycle Cycle Pump 174 ONOFF OFF Pump 176 OFF ON OFF Valve 178 OPEN CLOSED CLOSED Valve 180 OPENCLOSED CLOSED Valve 182 CLOSED OPEN OPEN Valve 184 CLOSED OPEN OPENValve 186 CLOSED OPEN CLOSED Valve 188 CLOSED CLOSED OPEN Valve 189CLOSED OPEN CLOSED Valve 190 CLOSED CLOSED OPEN

A more preferred embodiment of the present invention is shown in FIGS. 3a–3 d. Here, apparatus 200 includes a dual resin setup, wherein twoion-exchange resins are utilized such that one of the ion-exchangeresins can be in the service cycle while the other of the ion-exchangeresins undergoes the regeneration and rinse/refill cycles. Thus, itbecomes unnecessary to interrupt the copper removal process, because aservice cycle can be continuously performed by the apparatus.

Apparatus 200 includes a feed tank 214, which is operative to supplycopper bearing rinsewater stream 212 to a conduit 272 whichinterconnects various components of the apparatus 200. First resinvessel 218 and second resin vessel 219 are provided in fluidcommunication with conduit 272, and each resin vessel containsion-exchange resin 220 and 221, respectively. Rinse source 240 isfurther in fluid communication with conduit 272, and is operative toprovide de-ionized water 238. Regenerant source vessel 232 is operativeto provide acid 230, as appropriate for regeneration of ion exchangeresins 220 and 221. Waste outlet 224 is operative to receive copper freewaste 222 resulting from ion-exchange of copper bearing rinsewaterstream 212 with either of ion-exchange resins 220 or 221. Regenerantwaste collection 236 is operative to receive regenerant waste solution234, having copper salt present therein resulting from the regenerationof either of ion-exchange resins 220 or 221.

Pumps 274 and 276 are disposed in conduit 272 and are operative in an onstate to pump fluid through conduit 272. Valves 278 through 286, and 288through 290 are disposed in conduit 272 and are operative to movebetween a closed state preventing fluid flow therethrough and an openstate allowing fluid flow therethrough.

As shown in FIGS. 3 a and 3 b, first resin vessel 218 can undergo aservice cycle while second resin vessel 219 undergoes both aregeneration cycle and a rinse/refill cycle. In particular, as shown inFIG. 3 a, pumps 274 and 276 are turned on, valves 278, 280, 283, 285,286 and 289 are opened and valves 279, 281; 282, 284, 288 and 290 areclosed thereby to work a service cycle in first resin vessel 218 and aregeneration cycle in second resin vessel 219. With respect to theservice cycle of first resin vessel 218, copper bearing waste 212 ispassed in a preferably upflow direction through resin vessel 218, whereit undergoes ion-exchange with ion-exchange resin 220. Copper free waste222 resulting therefrom is sent to waste outlet 224. Concurrently, acid230 from regenerant source vessel 232 is pumped by pump 276 throughresin vessel 219 thereby to regenerate ion-exchange resin 221 to formcopper salt bearing regenerant waste 234 which is sent to regenerantwaste collection 236.

As shown in FIG. 3 b, once ion-exchange resin 221 is regenerated, arinse/refill cycle begins on second resin vessel 219, while the servicecycle continues on first resin vessel 218. Here, pump 276 is turned off,valves 288 and 290 open and valves 286 and 289 close. De-ionized water238 from rinse source 240 is passed through second resin vessel 219thereby to rinse away any excess acid and to form regenerant rinsesolution 240 which is passed to regenerant source vessel 232 for reusein forming the acid regenerant solution 230. Concentrated acid 292 maybe added to regenerant source vessel 232 to adjust the concentration ofacid regenerant solution 230 as desired.

Once the rinse/refill cycle has completed, valves 283, 285, 288 and 290are closed and the service cycle continues on first resin vessel 218until ion-exchange resin 220 is exhausted. Exhaustion of ion-exchangeresin 220 may be determined, for example, by measuring the concentrationand flow volume of copper bearing rinsewater stream 212 and comparingwith the known capacity of ion-exchange resin 220.

At this time, as shown in FIGS. 3 c and 3 d, second resin vessel 219undergoes a service cycle while first resin vessel 218 undergoesregeneration and rinse/refill cycles. In particular, as shown in FIG. 3c, pump 276 is turned on, valves 279, 281, 282, 284, 286 and 289 areopened and valves 278, 280, 283, 285, 288 and 290 are closed. Withrespect to the service cycle through second resin vessel 219, copperbearing rinsewater stream 212 from feed tank 214 is sent through secondresin vessel 219 thereby undergoing ion-exchange with ion-exchange resin221. Copper free waste 222 resulting therefrom is sent to waste outlet224. First resin vessel 218 undergoes regeneration as acid 230 is pumpedby pump 276 from regenerant source vessel 232 through first resin vessel218 thereby undergoing ion-exchange with ion-exchange resin 220 to formcopper salt bearing regenerant waste 234 which is sent to regenerantwaste collection 236.

As shown in FIG. 3 d, once ion-exchange resin 220 is regenerated, pump276 is turned off, valves 286 and 289 are closed and valves 288 and 290are opened. Second resin vessel 219 continues undergoing a servicecycle. De-ionized water 238 from rinse source 240 passes through firstresin vessel 218 thereby to rinse any excess acid therefrom. Theregenerant rinse solution 242 is then passed to regenerant source vessel232 where it is recycled for use in acid regenerant solution 230, theconcentration of which may be adjusted by addition of concentrated acidregenerant 292.

Once rinse/refill cycle has completed, valves 282, 284, 288 and 290 areclosed and the service cycle continues on second resin vessel 219 untilion-exchange resin 221 is exhausted. At this point, a service cycle onfirst resin vessel 218 and a regeneration cycle on second resin vessel219 begins again as shown in FIG. 3 a.

The various on/off and open/closed states of valves and pumps during theoperation cycles for apparatus 200 is summarized in Table 2 below:

TABLE 2 First resin First resin Second Second service service resinresin cycle/ cycle/ service service second second cycle/firstcycle/first resin regen. resin rinse resin regen. resin rinse cyclecycle cycle cycle Pump 274 ON ON ON ON Pump 276 ON OFF ON OFF Valve 278OPEN OPEN CLOSED CLOSED Valve 279 CLOSED CLOSED OPEN OPEN Valve 280 OPENOPEN CLOSED CLOSED Valve 281 CLOSED CLOSED OPEN OPEN Valve 282 CLOSEDCLOSED OPEN OPEN Valve 283 OPEN OPEN CLOSED CLOSED Valve 284 CLOSEDCLOSED OPEN OPEN Valve 285 OPEN OPEN CLOSED CLOSED Valve 286 OPEN CLOSEDOPEN CLOSED Valve 288 CLOSED OPEN CLOSED OPEN Valve 289 OPEN CLOSED OPENCLOSED Valve 290 CLOSED OPEN CLOSED OPEN

As shown in FIGS. 4 and 5, the present invention also includes thetreatment and processing of copper free waste resulting from theion-exchange of a copper bearing rinsewater stream according to thepresent invention. The treatment and processing as shown in FIGS. 4 and5 may be an add-on to the ion-exchange apparatus of the presentinvention, or may separately treat copper free waste from a singlesource, such as non Cu-CMP waste from the manufacturing process, or froma plurality of sources, such as numerous ion-exchange apparatus linkedto CMP or other tools, in a manufacturing process.

As shown in FIG. 4, an exemplary copper free waste treatment orprocessing apparatus 300 according to the present invention includes awaste tank 350 in fluid communication with a copper free waste source,such as an ion-exchange apparatus 304 which may be similar or identicalto the apparatus of FIGS. 2 a–2 c or 3 a–3 d. Here, copper free waste322, resulting from the ion-exchange of a copper bearing rinsewaterstream, is transferred from the waste source to a waste tank 350. Itshould be understood that waste tank 350 may be any type of fluidcontainer, collection vessel or conduit. Additionally, other copper freewaste to be disposed of, such as from non-copper CMP 344 or othersources, may be sent to waste tank 350 for treatment or processing.Since the copper free waste 322 and effluent from other sources may havelow pH and oxidizers such as H₂O₂, it is desirable to adjust the pH andORP of the copper free waste 322 in waste tank 350 so as to meetdisposal requirements, allowing efficient disposal of the wastesolution. Accordingly, the solution in waste tank 350 preferablyundergoes pH adjustment 352 and/or ORP adjustment 352′, as necessary.

In particular, a pH monitor 306 may be used to monitor the pH of copperfree waste 322 in waste tank 350. pH monitor 306 may signal to pumpeither a base or acid solution into waste tank 350 as necessary toadjust the pH of copper free waste 322 to a target pH. Specifically, pHmonitor 306 may signal to pump NaOH 307 into waste tank 350 when the pHof copper free waste 322 is below the target pH. Conversely, pH monitor306 may signal to pump H₂SO₄ into waste tank 350 when the pH of copperfree waste 322 is above the target pH. Similarly, ORP monitor 309 maysignal to pump NaHSO₃ 302 into waste tank 350 when anoxidation-reduction potential is detected. Treated waste 303 may then bedisposed of, such as by sending to sewer 305.

As shown in FIG. 5, an alternative waste treatment or processingapparatus 400 may be seen as an add-on to existing manufacturing tools,such as to one or more ion-exchange apparatus according to the presentinvention, as well as to non copper CMP tools and other sources ofcopper free waste. In particular, apparatus 400 allows the recycling ofwater from which copper has been removed, such as by the ion-exchangemethod and apparatus of the present invention. The recycled water can bereused at the CMP tool or in other manufacturing processes. It should beunderstood that apparatus 400 may be used to process rinse streams froma given tool as a “point of use” (POU) device, from several tools—suchas five tools—as a “local” device, or from all tools as a “facilities”device when rinse streams are combined and treated in a centrallocation. The use of apparatus 400 with the ion-exchange method andapparatus of the present invention provides an advantage in that solidsremoved and concentrated by apparatus 400 do not contain copper andtherefore can be disposed of as non-hazardous waste. With respect tocopper bearing regenerant waste resulting from the ion-exchange, it maybe desirable to send the regenerant waste from several sources,including point-of-use and local systems, to a facilities electrowinningcell for copper recovery, since electrowinning cells can be laborintensive at times.

In the exemplary embodiment, apparatus 400 includes waste tank 450 influid communication with a rinse stream source, such as an ion-exchangeapparatus 404 which may be similar or identical to the apparatus ofFIGS. 2 a–2 c or 3 a–3 d. It should be understood that rinse streamsfrom other sources, such as other manufacturing tools, may also beprocessed by apparatus 400. With respect to ion-exchange apparatus 404,copper free waste 422, resulting from the ion-exchange of a copperbearing rinsewater stream, is transferred from the waste source to thewaste tank 450. Copper free waste 422 may be completely free of copperions, although it should be understood that copper free waste 422 maycontain a small concentration of copper ions. Waste tank 450 may be anytype of fluid container, collection vessel or conduit.

A reducing agent 402 may be added to waste tank 450 to neutralizeoxidizers present in copper free waste 422. To the extent understood bythe ordinarily skilled artisan, an ORP monitor may be used to signal theaddition of reducing agent 402 when an oxidation-reduction potential isdetected. The reduced waste 460 then undergoes a reverse osmosis (R/O)process 493, which is preferably a double pass reverse osmosis system,thereby to remove organics and dissolved salts from the water. It shouldbe understood, however, that both single and multi-stage R/O processesare contemplated by the present invention. Apparatus 400 preferablyinclude a first stage R/O 494 and a second stage R/O 495, which includesR/O membranes 494′ and 495′ that have wide spacers to avoid plugging bythe solids. Exemplary membranes are Desal™ proprietary membrane productsmanufactured by Osmonics, 760 Shadowridge Dr., Vista, Calif. 92083.Alternatively, the R/O stages may utilize other types of membranesadapted for use with high solids in the seed stream, such as ceramicmembranes.

The reduced waste 460 is preferably first sent through first stage R/O494. The first stage R/O reject, or retentate, 496, which containscopper free solids, may be sent to drain. If solids removal is required,however, such as by local ordinances, the R/O reject 496 may be sent toa “facilities” solids removal system 497, which may receivesolid-bearing wastes from other systems as well. The first stage R/Opermeate 498 is then preferably sent through the second stage R/O 495.The second stage R/O reject 498 is preferably returned to waste tank450, and the second stage R/O permeate 499 is then preferably sentthrough an organic destruct UV lamp 409 and then a vacuum degasser 411for trace organics removal. Any lost volume of water from the R/O rejectcan be made up by adding ultrapure water 412, such as from the fabde-ionized water line, to the second stage R/O permeate 499 prior tosending second stage R/O permeate 499 through organic destruct UV lamp409.

After the UV/Vacuum degasification step 470, purified water 408 ispreferably sent to electro-deonization (EDI) system 406, which exchangesunwanted saline ions by exchanging them for either hydrogen or hydroxylions. Exemplary EDI units for use with the present invention aremanufactured by Electropure, in Laguna Hills, Calif. The EDI waste 407is preferably returned to waste tank 450. The resulting high puritywater 414 is preferably polished to 18.3 meg-ohm-cm resistivity water byEDI cell 406. High purity water 414 can then be recycled by returning itfor reuse in manufacturing and other processes.

It should be understood that the present invention contemplatesvariations on the above-described apparatus, such as variations in theselection and placement of components. In particular, the presentinvention contemplates waste processing apparatus that include one ormore of the components selected from the reducing agent 402, R/O process493, EDI unit 406, ultrapure water 412, UV lamp 409, and vacuumdegasification unit 411, in various combinations and orders.

As shown in FIG. 6, the present invention also contemplates a system fortreating copper bearing waste. In particular, the exemplary system 500includes a rinsewater stream source 510, such as a copper CMP tool,which is operative to provide copper bearing rinsewater stream 512 to anion-exchange apparatus 514 according to the present invention.Ion-exchange apparatus 514 is operative to provide a copper bearingregenerant waste 516 and a copper free waste 518. Copper bearingregenerant waste 516 may be sent for copper recovery to an optionalelectrowinning cell 520, such as a “facilities” electrowinning cell oran electrowinning cell as disclosed in application Ser. No. 09/322,745,filed May 28, 1999, entitled Electrowinning Cell Incorporating Metal IonFiltration Apparatus. It should be understood that other methods fordisposing of or recovering copper from copper bearing waste 516 are alsocontemplated by the present invention. Copper free waste 518 isoptionally sent to a waste treatment/processing apparatus 522, such asthat according to the present invention as described with reference toFIGS. 4 and 5. Again, it should be understood that other methods fortreating and/or disposing of copper free waste 518 are contemplated bythe present invention.

Accordingly, the present invention has been described with some degreeof particularity directed to the exemplary embodiments of the presentinvention. It should be appreciated, though, that the present inventionis defined by the following claims construed in light of the prior artso that modifications or changes may be made to the exemplaryembodiments of the present invention without departing from theinventive concepts contained herein.

1. A method for selectively removing metal ions of interest from asolution, comprising contacting a solution containing solid particles,an oxidizing agent and a first concentration of the metal ions with anion-exchange resin that is resistant to damage by the oxidizing agentand that is operative when in contact with the solution to exchangeselected ones of the metal ions in the solution for selected preferredions thereby to produce a treated solution having a second concentrationof the metal ions that is lower than the first concentration.
 2. Amethod according to claim 1 wherein the solution contains solidparticles having a size distribution of from 0.02 micron to 0.10 micron.3. A method according to claim 1 wherein the solution is wastewater froma chemical mechanical polishing process.
 4. A method according to claim1 wherein the metal ions of interest are copper ions.
 5. A methodaccording to claim 1 wherein said ion-exchange resin comprises aplurality of ion-exchange resin beads contained in a resin vesselthereby to define a resin bed, and wherein the step of contacting isaccomplished by passing the solution in an up-flow direction throughsaid resin vessel thereby to expand the resin bed.
 6. A method accordingto claim 5 wherein the resin bed is expanded by 10% to 60%.
 7. A methodaccording to claim 1 wherein said ion-exchange resin is a crosslinkedpoly-4-vinylpyridine resin.
 8. A method according to claim 7 whereinsaid ion-exchange resin is selected from the group consisting of Reillex402 and Reillex 425 resins.
 9. A method according to claim 1 includingthe step of contacting the ion-exchange resin with a regenerant solutionoperative to exchange ions therein for the metal ions of interestcontained in the ion-exchange resin, thereby to form a regenerant wastesolution containing a salt of the metal ions of interest.
 10. A methodaccording to claim 9 wherein the regenerant solution is selected fromthe group consisting of an acid solution and a base solution.
 11. Amethod according to claim 10 wherein said acid solution is sulfuric acidand wherein said base solution is ammonium hydroxide.
 12. A methodaccording to claim 9 wherein the regenerant waste solution is passed toan electrowinning cell that is operative to reduce the metal ions totheir corresponding elementary metal.
 13. A method according to claim 9including the step of contacting the ion-exchange resin with a firstrinse solution thereby to form a second rinse solution.
 14. A methodaccording to claim 13 wherein the first rinse solution is de-ionizedwater.
 15. A method according to claim 13 wherein the second rinsesolution is passed to a regenerant source vessel, and including the stepof adding a regenerant concentrate to the second rinse solution in theregenerant source vessel thereby to form the regenerant solution in theregenerant source vessel.
 16. A method according to claim 1 wherein saidsecond concentration of metal ions is substantially zero.
 17. A methodaccording to claim 1 including the steps of adjusting the pH andoxidation-reduction potential of said treated solution.
 18. A methodaccording to claim 1 including the step of filtering the treatedsolution by reverse osmosis thereby to produce a retentate and apermeate.
 19. A method according to claim 18 including the step ofadding a reducing agent to the treated solution prior to the step offiltering.
 20. A method according to claim 18 including the step ofpassing the permeate through an electro-deionization system.
 21. Amethod according to claim 18 including the step of passing the permeatethrough a UV/vacuum degasification system.
 22. A method according toclaim 18 including the step of adding water to the permeate.
 23. Amethod for selectively removing metal ions of interest from a solutioncontaining the metal ions, solid particles and an oxidizing agentwithout removing the solid particles and oxidizing agent from thesolution, comprising contacting the solution with an ion-exchange resinthat is resistant to damage by the oxidizing agent and that is operativewhen in contact with the solution to exchange the metal ions in thesolution for selected preferred ions thereby to produce a treatedsolution containing the solid particles and the oxidizing agent.
 24. Amethod for selectively removing copper ions from a solution containingthe copper ions, solid particles and an oxidizing agent, comprisingcontacting the solution with a crosslinked poly-4-vinylpyridineion-exchange resin.
 25. A method for selectively removing copper ionsfrom a solution containing the copper ions and aluminum ions, comprisingcontacting the solution with a crosslinked poly-4-vinylpyridineion-exchange resin thereby to produce a treated solution containing thealuminum ions.
 26. An apparatus for selectively removing metal ions ofinterest from a solution containing an oxidizing agent, solid particlesand a first concentration of the metal ions, comprising: (a) an inletadapted to receive the solution from a solution source; (b) a resinvessel in fluid communication with said inlet and adapted to receive thesolution therefrom; (c) an ion-exchange resin disposed in said resinvessel, wherein said ion-exchange resin is resistant to damage by theoxidizing agent and is operative when in contact with the solution toexchange selected ones of the metal ions in the solution for selectedpreferred ions thereby to produce a treated solution having a secondconcentration of the metal ions that is lower than the firstconcentration; (d) a first outlet in fluid communication with the resinvessel and adapted to receive the treated solution therefrom; (e) aregenerant source in fluid communication with said resin vessel andoperative to selectively provide thereto a regenerant solution that isoperative when in contact with the ion-exchange resin to exchange ionsin the regenerant solution for the metal ions of interest contained inthe ion-exchange resin, thereby to form a regenerant waste solutioncontaining a salt of the metal ions of interest; (f) a second outlet influid communication with said resin vessel and adapted to receive theregenerant waste solution therefrom; and (g) a valve system comprising aplurality of valves associated with a plurality of fluid pathwaysinterconnecting selected ones of said inlet, said resin vessel, saidregenerant source and said first and second outlets, whereby in a firststate said valve system permits fluid flow through said inlet, throughsaid resin vessel and through said first outlet thereby to define afirst fluid pathway, and in a second state said valve system permitsfluid flow from said regenerant source, through said resin vessel andthrough said second outlet thereby to define a second fluid pathway. 27.An apparatus according to claim 26 wherein said second outlet is adaptedto be placed in fluid communication with an electrowinning cell and toprovide the regenerant waste solution thereto.
 28. An apparatusaccording to claim 26 including a rinse source in fluid communicationwith said resin vessel and operative to provide a rinse solutionthereto, and wherein said valve system includes a third state wherebysaid valve system permits fluid flow from said rinse source, throughsaid resin vessel and to said regenerant source thereby to define athird fluid pathway.
 29. An apparatus according to claim 26 including areservoir adapted to receive said treated solution from said firstoutlet, and including a pH monitor operative to monitor a pH of saidtreated solution in said reservoir and an oxidation-reduction potentialmonitor operative to monitor an oxidation-reduction potential of saidtreated solution in said reservoir, and including an acid source, a basesource and a reducing agent source each in fluid communication with saidreservoir, whereby said pH monitor is capable of selectively signalingsaid acid source and said base source to provide acid and baserespectively to said reservoir thereby to attain a target pH of saidtreated solution in said reservoir, and whereby said oxidation-reductionpotential monitor is capable of signaling said reducing agent source toprovide a reducing agent to said reservoir thereby to attain a targetoxidation-reduction potential of said treated solution in saidreservoir.
 30. An apparatus according to claim 29 wherein said reservoiris in fluid communication with a sewer and is operative to provide saidtreated solution thereto.
 31. An apparatus according to claim 26including a reservoir adapted to receive said treated solution from saidfirst outlet, and including a reducing agent source in fluidcommunication with said reservoir and operative to provide a reducingagent thereto, a reverse-osmosis device in fluid communication with saidreservoir and adapted to receive said treated solution therefrom andoperative to filter said treated solution thereby to produce a retentateand a permeate, a UV/vacuum degasification unit in fluid communicationwith said reverse-osmosis device and adapted to receive said permeatetherefrom and operative to remove organic materials present in saidpermeate thereby to produce purified water, and an electro-deionizationunit in fluid communication with said UV/vacuum degasification unit andadapted to receive said purified water therefrom and operative toexchange saline ions present in said purified water for ions selectedfrom the group consisting of hydrogen or hydroxyl ions thereby toproduce high purity water.
 32. An apparatus according to claim 31wherein said reverse osmosis device includes a first-stage reverseosmosis element operative to filter said treated solution thereby toproduce a first-stage retentate and a first-stage permeate, and whereinsaid reverse osmosis device includes a second-stage reverse osmosiselement operative to filter said first-stage permeate into asecond-stage retentate and said permeate.
 33. An apparatus forselectively removing metal ions of interest from a solution containingan oxidizing agent, solid particles and a first concentration of themetal ions, comprising: (a) an inlet adapted to receive the solutionfrom a solution source; (b) a first resin vessel in fluid communicationwith said inlet and adapted to receive the solution therefrom; (c) afirst ion-exchange resin disposed in said first resin vessel, whereinsaid first ion-exchange resin is resistant to damage by the oxidizingagent and is operative when in contact with the solution to exchangeselected ones of the metal ions in the solution for selected preferredions thereby to produce a treated solution having a second concentrationof the metal ions that is lower than the first concentration; (d) asecond resin vessel in fluid communication with said inlet and adaptedto receive the solution therefrom; (e) a second ion-exchange resindisposed in said second resin vessel, wherein said second ion-exchangeresin is resistant to damage by the oxidizing agent and is operativewhen in contact with the solution to exchange selected ones of the metalions in the solution for selected preferred ions thereby to produce atreated solution having a second concentration of the metal ions that islower than the first concentration; (f) a first outlet in fluidcommunication with said first resin vessel and said second resin vesseland adapted to selectively receive the treated solution therefrom; (g) aregenerant source in fluid communication with said first resin vesseland said second resin vessel and operative to selectively providethereto a regenerant solution that is operative when in contact with thefirst and second ion-exchange resin respectively to exchange ions in theregenerant solution for the metal ions of interest contained in thefirst and second ion-exchange resin respectively, thereby to form aregenerant waste solution containing a salt of the metal ions ofinterest; (h) a second outlet in fluid communication with said firstresin vessel and said second resin vessel and adapted to selectivelyreceive the regenerant waste solution therefrom; and (i) a valve systemcomprising a plurality of valves associated with a plurality of fluidpathways interconnecting selected ones of said inlet, said first andsecond resin vessel, said regenerant source and said first and secondoutlets, whereby in a first state said valve system permits fluid flowthrough said inlet, through said first resin vessel and through saidfirst outlet thereby to define a first fluid pathway, and permits fluidflow from said regenerant source, through said second resin vessel andthrough said second outlet thereby to define a second fluid pathway, andin a second state said valve system permits fluid flow through saidinlet, through said second resin vessel and through said first outletthereby to define a third fluid pathway, and permits fluid flow fromsaid regenerant source, through said first resin vessel and through saidsecond outlet thereby to define a fourth fluid pathway.
 34. An apparatusaccording to claim 33 including a rinse source in fluid communicationwith said first and second resin vessel and operative to provide a rinsesolution thereto, and wherein said valve system includes a third statewhereby said valve system permits fluid flow from said rinse source,through said first resin vessel and to said regenerant source thereby todefine a fifth fluid pathway and permits fluid flow along said thirdfluid pathway, and wherein said valve system includes a sixth statewhereby said valve system permits fluid flow from said rinse source,through said second resin vessel and to said regenerant source therebyto define a fifth fluid pathway and permits fluid flow along said firstfluid pathway.
 35. A system for removing metal ions of interest from asolution containing solid particles, an oxidizing agent and a firstconcentration of the metal ions, comprising: (a) a solution sourceoperative to provide the solution containing the solid particles, theoxidizing agent and the first concentration of the metal ions; (b) anion-exchange apparatus in fluid communication with the solution sourceand operative to receive the solution therefrom, wherein theion-exchange apparatus includes an ion-exchange resin that is resistantto damage by the oxidizing agent and that is operative when in contactwith the solution to exchange selected ones of the metal ions in thesolution for selected preferred ions thereby to produce a treatedsolution having a second concentration of the metal ions that is lowerthan the first concentration, and wherein the ion-exchange apparatusincludes a regenerant source operative to provide a regenerant solutionthat is operative when in contact with the ion-exchange resin toexchange ions in the regenerant solution for the metal ions of interestcontained in the ion-exchange resin, thereby to form a regenerant wastesolution containing a salt of the metal ions of interest; and (c) ametal recovery apparatus in fluid communication with said ion-exchangeapparatus and adapted to receive the regenerant waste solutiontherefrom, wherein the metal recovery apparatus is operative to recoverthe metal ions of interest from the regenerant waste solution.
 36. Asystem according to claim 35 including a waste processing apparatus influid communication with said ion-exchange apparatus and adapted toreceive said treated solution therefrom, wherein said waste processingapparatus includes at least one device selected from the groupconsisting of a reverse-osmosis device, a UV/vacuum degasificationdevice and an electro-deionization device, wherein said waste processingapparatus is operative to remove contaminants from said treated solutionthereby to produce high purity water.
 37. A system according to claim 35including a waste processing apparatus in fluid communication with saidion-exchange apparatus and adapted to receive said treated solutiontherefrom, wherein said waste processing apparatus is operative toadjust a pH of said treated solution to a target pH and is operative toadjust an oxidation-reduction potential of said treated solution to atarget oxidation-reduction potential.
 38. A system according to claim 35wherein said metal recovery apparatus is an electrowinning celloperative to reduce the metal ions in the regenerant waste solution totheir corresponding elementary metal.